Background: Abnormally low or high blood iron levels are common health conditions worldwide and can seriously affect an individual’s overall well-being. A low-cost point-of-care technology that measures blood iron markers with a goal of both preventing and treating iron-related disorders represents a significant advancement in medical care delivery systems. Methods: A novel assay equipped with an accurate, storable, and robust dry sensor strip, as well as a smartphone mount and (iPhone) app is used to measure total iron in human serum. The sensor strip has a vertical flow design and is based on an optimized chemical reaction. The reaction strips iron ions from blood-transport proteins, reduces Fe(III) to Fe(II), and chelates Fe(II) with ferene, with the change indicated by a blue color on the strip. The smartphone mount is robust and controls the light source of the color reading App, which is calibrated to obtain output iron concentration results. The real serum samples are then used to assess iron concentrations from the new assay, and validated through intra-laboratory and inter-laboratory experiments. The intra-laboratory validation uses an optimized iron detection assay with multi-well plate spectrophotometry. The inter-laboratory validation method is performed in a commercial testing facility (LabCorp). Results: The novel assay with the dry sensor strip and smartphone mount, and App is seen to be sensitive to iron detection with a dynamic range of 50 – $300~\mu \text{g}$ /dL, sensitivity of 0.00049 a.u/ $\mu \text{g}$ /dL, coefficient of variation (CV) of 10.5%, and an estimated detection limit of $\sim 15~\mu \text{g}$ /dL These analytical specifications are useful for predicting iron deficiency and overloads. The optimized reference method has a sensitivity of 0.00093 a.u/ $\mu \text{g}$ /dL and CV of 2.2%. The correlation of serum iron concentrations (N = 20) between the optimized reference method and the novel assay renders a slope of 0.95, and a regression coefficient of 0.98, suggesting that the new assay is accurate. Last, a spectrophotometric study of the iron detection reaction kinetics is seen to reveal the reaction order for iron and chelating agent. Conclusion: The new assay is able to provide accurate results in intra- and inter- laboraty validations, and has promising features of both mobility and low-cost manufacturing suitable for global healthcare settings.

中文翻译：

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使用基于智能手机的新型检测方法测量人血清中的总铁


背景：血铁水平异常低或高是全世界常见的健康状况，会严重影响个人的整体健康。一种测量血液铁标记物的低成本护理点技术，旨在预防和治疗与铁相关的疾病，代表了医疗保健服务系统的重大进步。方法：一种新颖的检测方法配备了准确、可存储且坚固的干传感器条以及智能手机支架和 (iPhone) 应用程序，用于测量人血清中的总铁。传感器带采用垂直流动设计，基于优化的化学反应。该反应从血液转运蛋白中剥离铁离子，将 Fe(III) 还原为 Fe(II)，并将 Fe(II) 与铁烯螯合，条带上的蓝色表示变化。智能手机支架坚固耐用，可控制颜色读取应用程序的光源，该应用程序经过校准以获得输出铁浓度结果。然后使用真实的血清样本来评估新测定中的铁浓度，并通过实验室内和实验室间实验进行验证。实验室内验证使用优化的铁检测方法和多孔板分光光度法。实验室间验证方法在商业测试设施 (LabCorp) 中进行。结果：采用干传感器带和智能手机支架的新颖测定法和应用程序被认为对铁检测敏感，动态范围为 50 – $300~\mu \text{g}$ /dL，灵敏度0.00049 au/ $\mu \文本{g}$ /dL，变异系数 (CV) 为 10。5%，估计检测限为$\sim 15~\mu \text{g}$ /dL 这些分析指标对于预测铁缺乏和铁过载非常有用。优化后的参考方法灵敏度为0.00093 au/ $\mu \文本{g}$ /dL 和 CV 为 2.2%。优化参考方法与新测定法之间的血清铁浓度相关性 (N = 20) 的斜率为 0.95，回归系数为 0.98，表明新测定法是准确的。最后，铁检测反应动力学的分光光度研究揭示了铁和螯合剂的反应级。结论：新的检测方法能够在实验室内和实验室间验证中提供准确的结果，并具有适用于全球医疗保健环境的移动性和低成本制造的良好特性。